1. Field of the Invention
The present invention relates to an exchangeable type ink tank and an ink-jet printing apparatus employing the ink tank. More specifically, the invention relates to a cartridge type ink tank having an ink storage chamber and a waste ink storage chamber.
2. Description of the Related Art
As one example of a conventional ink tank, there has been known an ink cartridge in a form illustrated in FIGS. 1A and 1B. FIG. 1A is a sectional side elevation of the ink cartridge and FIG. 1B is a front elevation thereof.
As shown in the sectional side elevation, the ink cartridge includes an ink storage chamber 1 and a waste ink storage chamber 2. At respective positions on an end of the ink storage chamber 1, there are provided two rubber plugs 4 to be pierced by an ink supply needle provided on a main body of an ink-jet printing apparatus. Similarly, one rubber plug 4 is also provided at one position on an end of the waste storage chamber 2. These rubber plugs 4 are constructed to be clamped by a casing member 10A of the ink cartridge, an ink absorbing member 6 and a rubber plug retainer 7 except for portions to be pierced by the needles. With such construction, when the ink cartridge is removed from the main body of the printing apparatus, an ink adhering on the supply needle can be removed by the ink absorbing member 6 so as to prevent contamination of an inside of the printing apparatus by the ink adhering on the supply needle or plugging of the supply needle per se.
The waste ink storage chamber 2 is constructed with two layers of storage portions which are communicated with each other at one end of the chamber. A portion of the plug to be pierced by the ink supply needle is located corresponding to the storage portion of the lower layer. Through the rubber plug 4 of the waste ink storage chamber 2, the ink supply needle communicated with a discharge passage of the ink-jet printing apparatus pierces. By this a waste ink discharged during ejection recovery process or so forth flows into the lower layer of the storage portion of the waste ink storage chamber 2. Substantially entire space of the waste ink storage chamber 2 is filled with an absorbing member 8 so that the absorbing member 8 can absorb the waste ink flown into the lower layer of the storage portion. According to in-flow of the waste ink, a portion of the absorbing member 8 maintaining the waste ink is gradually spread to reach the absorbing body 8 in the upper layer storage portion, and a part of the waste ink absorbed exudes out of the absorbing body. On the other hand, a partitioning wall 2A is provided adjacent to the end of the absorbing member 8 in the upper storage portion of the waste ink storage chamber 2. By this, while the waste ink amount does not exceed a waste ink storage capacity of the absorbing member, an exuded ink may not flow over the partitioning wall 2A to enter into a space where the absorbing member 8 is not provided. When the accumulated waste ink amount in the waste ink storage chamber 2 exceeds the waste ink storage capacity, an amount of the exuded ink is one so that the waste ink also overflows the partitioning wall 2A to enter into the space at right side of the wall 2A. Then, a level of the waste ink in the right side space is elevated according to increasing of the waste ink flowing into the space, so that the waste ink in the right side space comes into contact with predetermined waste ink detecting electrodes 301a and 301b.
One end of each of the electrodes 301a and 301b (in FIG. 1A wherein only electrode 301b is illustrated) projects into the right side space defined by the partitioning wall 2A. On the other hand, the other end of each of these electrodes is arranged to be exposed to the end face of the ink cartridge (see FIG. 1B). Then, the electrodes exposed at the side of the end face may come into contact with a predetermined electrodes at the main body of the printing apparatus when the ink cartridge is loaded in the main body of the printing apparatus. With such construction, when the waste ink amount in the waste ink storage chamber 2 is increased so that two electrodes 301a and 301b conduct each other via the waste ink, the waste ink reaching the predetermined amount can be detected by the main body of the printing apparatus. As a result, measure, such as exchanging of the ink cartridge 1 or so forth can be taken by the printing apparatus.
Further, at an upper portion of a rear end portion of the waste ink storage chamber 2, an atmosphere communicating portion 9 is provided. Via this atmosphere communicating portion 9, an inside of the waste ink storage chamber 2 and atmosphere in an outside of the ink cartridge can be communicated with each other.
However, since the conventional ink tank is constructed by integrally forming the ink storage chamber 1 and the waste ink storage chamber 2, the following problems exist mainly in view of construction.
In the conventional ink cartridge, when the waste ink detecting electrodes are provided as set forth above, a step for forming a hole in the wall of the waste ink storage chamber for inserting the electrode becomes necessary. Also, since the hole is formed, sealing an around potion of the hole after installation of the electrode becomes necessary. By this, number of steps in production of the ink tank is increased. Furthermore, if the seal is incomplete, the waste ink may leak to degrade reliability of the waste ink storage chamber. Also, in formation of sealing, it is possible that a sealing member covers the electrodes to cause failure of the operation of the electrode.
Further, in the construction of the conventional waste ink detection as set forth above, in certain attitude in loading of the ink cartridge or in certain attitude of the printer, in which the ink cartridge is loaded, it is possible that the waste ink leaks through the atmosphere communicating portion 9 before the waste ink reaching the predetermined amount is detected by the waste ink detecting electrodes.